The present invention relates to fiber reinforced resin fishing rods and more particularly to such rods fabricated in tubular, hollow core sections, wherein rod sections are joined by means of non-metallic ferrules.
The majority of fishing rods manufactured at the present time are fabricated of fiber reinforced resins in multiple sections. In the recent past, nearly all of these rods have been fabricated in sections from fiber reinforced resin fabrics that are wrapped about tapered, elongated mandrels and heated at elevated temperatures to cure the resin, thereby providing tapered, hollow core, tubular rod blanks. These rod blanks are then finished by the addition of line guides, handles and reel seats (to rod butt sections) and ferrules (at mated rod section ends).
Substantial emphasis is placed on ferrule design inasmuch as the interlocking, telescopic joints provided by ferrules tend to constitute dead spots in the assembled rods that markedly affect the overall rod performance. Metallic ferrules are being rapidly replaced with non-metallic ferrules of various designs. These non-metallic ferrules not only are intended to secure the rod sections together in axial alignment -- as were the metallic ferrules -- but also are intended to flex during use in order to minimize the effects of ferrule joints on overall rod performance. The design criteria are stringent inasmuch as a ferrule joint must be capable of withstanding substantial forces in use and must be capable of being produced economically, in addition to being as flexible as possible.
Three general categories of non-metallic ferrule joints have been utilized. One of the most common is patterned after the metallic ferrule in that a tubular reinforced resin sleeve is secured to the outer surface of the end of one rod blank section and extended axially outward to provide a tubular recess into which the end of another rod blank section may be telescopically inserted to frictionally interlock the rod sections together; the telescopically insertable rod blank end being provided with a counter, if desired as in U.S. Pat. No. 3,152,800 to Giampa et al, or otherwise reinforced to withstand the forces to which the joint will be subjected as in U.S. Pat. No. 3,835,569 to Gould, III et al. Another ferrule joint employs a tubular insert that is secured to the inner surface of the end of one rod section and extended axially outward to provide a tubular sleeve over which the end of another rod blank section may be telescopically engaged to frictionally interlock the rod sections together; the rod blank ends being appropriately reinforced to withstand the forces to which the joint will be subjected as in U.S. Pat. No. 3,613,287 to Grein. The third ferrule joint category utilizes the end of one rod section itself as the ferrule with the end of another rod section telescopically insertable into the rod section ferrule end to frictionally interlock the rod sections together; the rod section ferrule end being exteriorly reinforced as in U.S. Pat. No. 3,186,122 to Clock et al, or interiorly reinforced as in U.S. Pat. No. 3,830,008 to Johnson.
Ferrules of the above-mentioned categories, although generally satisfactory, have been limited, heretofore, primarily to so-called "fiberglass" rods which are composed of longitudinal strands of glass fiber embedded in a polymerized resin. Such fiberglass rod blanks are fabricated in tapered, tubular form of relatively large diameters to provide adequate section modulii along their length to withstand the forces to which they are subjected and to provide desired degrees of stiffness. However, the ferrule designs known heretofore are inadequate for use in rod construction employing stiffer reinforcing fibers such as graphite and boron wherein the rod blank cross sections are significantly smaller for desired degrees of stiffness. Such ferrule designs, when applied to graphite rods as an example, are either structurally inferior, or too inflexible, or so bulky as to be unsightly or a combination of the above, all of which constitute deficiencies rendering the overall rod design unacceptable. Furthermore, ferrules of the above-mentioned categories often require time consuming or complicated fabrication techniques that seriously affect the economical production of rods utilizing such ferrules.